1. Field of the Invention
This invention relates to cleaning devices for ink jet type printers and, more particularly, to a rotary cleaning device for ink jet printers which removes contaminants such as ink and dust from the nozzle-containing face of a printhead by rotation of at least one flexible blade member.
2. Description of the Related Art
In ink jet printers of the carriage type, a printhead containing a plurality of nozzles is located on a carriage which is reciprocated across a printing zone to effect printing onto a recording medium (i.e., paper). Due to the close tolerances between the recording medium and the nozzles and the small size of the nozzle outlets, it is common for such nozzles to become clogged and perform unreliably due to contaminants becoming lodged in the nozzles and on the front face of the printhead. Additionally, ink and other contaminants which collect on the front face of the printhead can also have an adverse influence on the formation of droplets made by the nozzles. Numerous devices attempt to remove collected ink and other contaminants from the nozzle-containing faces of printheads in various ways.
U.S. Pat. No. 4,745,414 to Okamura et al discloses a recovery device for an ink jet recorder which includes a wiping blade which can be advanced to contact or retracted to be spaced from the nozzle-containing face of a printhead. Movement of the printhead along a carriage path relative to the laterally stationary wiping blade provides the wiping action. The construction of Okamura et al tends to fling the material removed from the printhead nozzle face into adjacent portions of the printer. It is also impossible to wipe the nozzle face more than once without reciprocating the printhead along the carriage path which reciprocation is not easily obtained.
U.S. Pat. No. 4,401,990 to Aiba et al discloses a nozzle cleaning device for an ink jet printer system in which a nozzle and a slidable member are disposed on a carriage. The slidable member includes an absorptive cleaning pad which either covers the nozzle the entire time the printer is off or only momentarily when the printer is turned on. The cleaning pad is of a nonwoven cloth and only serves to absorb liquid ink from the nozzle. The device of Aiba et al provides no means for washing of the nozzle and only wipes the nozzle momentarily when the slidable member first approaches the nozzle.
U.S. Pat. No. 4,371,881 to Bork et al discloses a pivotal shield for an ink jet recording device head whereby the shield is movable relative to the writing head to shield, wipe and permit flushing of the writing head outlets. The device of Bork et al uses a resilient wiper element which engages the writing head surface and provides a vertical wiping motion to remove ink from the head.
U.S. Pat. No. 4,853,717 to Harmon et al discloses a service station for an ink jet printer which comprises a pump means for priming an ink jet cartridge, a sled to actuate the service station and a wiping blade for cleaning the printhead. The wiping blade is a stationary resilient piece of rubber which is mounted on a stationary bracket. The wiper is located in the path of the printhead carriage so that it wipes the nozzle-containing face of the printhead during a portion of the printhead travel path. The construction of Harmon et al also tends to fling material removed from the printhead into adjacent portions of the printer and the wiping motion cannot be repeated without reciprocating the printhead and carriage.
U.S. Pat. No. 4,112,435 to Kattner et al discloses a cover and cleaning device for an ink jet recorder which has a wiping arm which wipes the nozzle-containing face of a writing head during movement between a blocking position and an operative position. Once again, this device tends to fling material removed from the printhead into surrounding portions of the printer.
U.S. Pat. No. 4,370,050 to Matsui et al discloses a pre-transfer cleaning device for an image transfer copying apparatus which has a longitudinally extending cleaning pad of foamed polyurethane which frictionally contacts the surface of a dielectric face to remove dust. The pad is retractable to engage with a brush which cleans the pad and removes the dust into an underlying receptacle. The device of Matsui et al does not clean ink jet printheads.
U.S. Pat. No. 4,706,320 to Swift discloses an electrostatic cleaning brush comprising a cylindrical core and spirally wound fabric. The cleaning brush is rotated by a D.C. motor and cleans a photoconductive belt by electrostatic attraction. The device of Swift does not include a wiping blade and does not clean an ink jet printhead.
U.S. Pat. No. 4,252,448 to Johnson et al discloses a head cleaning apparatus for an electroresistive printer which has a cleaning brush. The head moves over the brush in a first direction and then immediately back in a reverse direction while pulling the head away from the brush. The cleaning brush of Johnson et al tends to fling material into adjacent printer components.
U.S. Pat. No. 4,177,471 to Mitchell discloses a carriage for an ink jet printer. The printer includes a cap which is positioned over a printhead array during non-use. Ink left on the cap is removed from the cap by a doctor blade and a pad wet with glycerine.
Most of the above-mentioned devices provide some degree of cleaning of ink jet printhead nozzle-containing faces. A problem with these cleaning devices is that they fling ink and other contaminants to surrounding portions of the printer and, in particular, onto the recording medium. Additionally, with the devices which rely upon the carriage movement to move the printhead over the cleaning blade, it is difficult to repeat the cleaning action since the entire carriage must be reciprocated. Another problem is the difficulty in removing dried ink from nozzle faces with just a wiping blade. A further problem, not addressed in previous ink jet cleaning devices, is the deteriorating efficiency of wiping blades due to the accumulation of dried ink and other contaminants on the cleaning blade. Once the blade has removed ink from a printhead face, the blade needs to have the ink removed therefrom so that the ink and other contaminants do not accumulate on the blade.